Can i rectify mistakes from 2008

In 2008 I prepared my tax return using an online portal. Due to my incorrect and incomplete understanding of using the portal + some glitches (I think) in the portal s/w, some mistakes crept into the return. Now when I see the return (due an IT dept demand order), I see the following mistakes in my return: - I reported Salary amount including the sec 10 deductible allowance when actually I should have reported amount excluding the deductible allowance - My home loan interest payment created a loss on House property income. It got updated correctly in the CYLA schedule. BUT, the Salary amount was not adjusted to subtract the loss amount. - I paid a tax amount as under "Regular Assessment" instead of "Self Assessment". SO, Self assessment shows zero on the return. With the 3 mistakes above, the tax amount payable was different than what I computed and the resulting 234B/C interest amounts, etc. are different. Is it possible to correct that mistake now?